


Regretti

by skeletonfricker



Category: Undertale (Video Game)
Genre: Abuse, Belly Kink, Force-Feeding, Incestuous Undertones, It's a thing now, M/M, Non-Consensual Tickling, Tickling, Yandere Papyrus, Yes Really
Language: English
Status: Completed
Published: 2015-12-30
Updated: 2015-12-30
Packaged: 2018-05-10 09:44:30
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,894
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5581030
Author URL: https://archiveofourown.org/users/skeletonfricker/pseuds/skeletonfricker
Summary: <blockquote class="userstuff">
              <p>When you’re the brother of a guy like Papyrus, you have to expect to put up with a lot of crap. And 99% of the time, Sans was more than willing to do just that. This was the 1%. </p>
<p>“Papyrus,” Sans said in a dangerously low voice, “untie me right now.”</p>
<p>“I will!” He turned away, spooning spaghetti onto a plate. “I will. Just as soon as you’ve eaten my spaghetti.”</p>
            </blockquote>





	Regretti

**Author's Note:**

> Dedicated to my friend who inspired me to write this, we're both steeped in sin. I'm sorry.

It was late when Sans stepped into the home he and Papyrus shared. He could hear his brother banging around in the kitchen. Sans was a little surprised to see Papyrus cooking at this hour, but then, that’s Papyrus for you.

 

“Is that you, Sans?” Papyrus called from the kitchen.

 

“Yup.” Sans leaned over to peer into the kitchen. Papyrus was wearing his apron and was tending to a large boiling pot on the stove. He turned to look at Sans, beaming.

 

“You’re home late! But you’re just in time to have some of my excellent spaghetti!” He dipped his spoon in the pot and pulled up a scoop of the long stringy noodles, giving Sans a wink. “Nothing but the best for my brother!”

 

Sans winced. “Sorry bro, I already ate at Grilby’s.” He had honestly overdone it, too. The excess magic from the food had pooled into the space beneath his rib cage, creating a pale blue translucent stomach. He could feel it pressing against him, full and heavy.

 

“Maybe tomorrow, huh?” He felt a little bad. He was usually happy to eat whatever Papyrus cooked, even if it was wretched (and let’s be real, it usually was). But tonight there was no way he could stomach it.

 

When he didn’t hear a response from Papyrus right away, he looked back in the kitchen, puzzled. Papyrus had his back to him, and he was standing very still. Slowly, he reached back and undid the apron, pulling it over his head.

 

Sans jumped as Papyrus suddenly violently slammed the apron down on the counter with a loud bang. He hunched over the counter, his hands balled into fists.

 

“B-Bro?”

 

When Papyrus spoke, his voice was unusually quiet, almost a hiss. “What kind of idiot -”

 

He turned his head suddenly to look at Sans, his voice raising in intensity. “ - DO YOU TAKE ME FOR!?”

 

Sans stared in shock. His brother looked - scary, honestly. His face was a mask of rage, his usual pleasant smile completely gone. Papyrus turned fully and began to walk slowly but methodically towards his brother, his hands constantly clenching and unclenching.

 

Sans reflexively stepped back. “Bro - wh-wha -“

 

“I KNOW you’re not here this late because you were at that filthy GREASEHOLE again.” Papyrus’ voice was hard, every syllable like a dagger.

 

“B-But uh - I was! Honestly!” Something about Papyrus’ sudden change of demeanor was making Sans very nervous.

 

Suddenly Papyrus reached out and grabbed the hem of Sans’ shirt, yanking it up so hard he almost lifted Sans off the ground. Sans made a choked sound of surprise.

 

“God, I can see you GORGED yourself!” Papyrus said, disgusted. “Have you no self-control?”

 

“H-Hey!” Sans grabbed the shirt back and quickly pulled it down, flustered. Papyrus had criticized his eating habits before, but this was quickly escalating into something ugly that Sans didn’t know how to deal with.

 

“And where were you BEFORE that, hmm?” Papyrus loomed over Sans, becoming smug. “You were at that DOOR again, weren’t you!?”

 

“Wh-what?” Did he mean the door in the woods? “H-How do you even know about tha -“

 

“I wanted to know where you kept sneaking off to, so I followed you!” Papyrus began to circle Sans like a hawk. “You think you’re so stealthy, but you never knew I was there! And then I saw you, exchanging jokes with some strange woman behind a door!”

 

Sans’ mind was reeling. “Wait, back up - you were - FOLLOWING me -?”

 

“What are you even thinking, talking to that woman!?” Papyrus continued, undaunted. “Who even IS she!? Are MY jokes not good enough, that you have to go talk to strangers in the woods!? She could be dangerous! What if she attacked you, could you even defend yourself with your 1 HP!?”

 

“P-Pap, she’s - she’s just a lonely old lady, I -“ Sans stopped, frowning. Why was he trying to justify himself? He didn’t do anything wrong, and it was hardly Papyrus’ business anyway. “Look, I can chat with strange ladies behind doors if I feel like it! What do YOU care!?”

 

Papyrus reared up like a cobra, eyes going wide. “What - what do _I_ care?” His voice was shrill. “What do I _care_? I care about YOU! Everything I do, I do for YOU. I cook, I clean, I look after you - but you don’t appreciate it!”

 

“That’s not true -“

 

“Well you’re GOING to start appreciating me, brother!” Papyrus raised a hand high, magic crackling in the air. Sans suddenly felt pressure in his chest as his soul turned blue. “And you’re GOING to start TODAY!”

 

Before Sans could react, Papyrus brought his hand down hard, and everything went black.

 

 

Sans groaned as he came to, his head throbbing. What did he do last night? He tried to put his hand on his head, but found with some alarm he couldn’t move it. He couldn’t move his arms at all. Eyes opening wide, he realized he wasn’t even in his room. He was in the kitchen, sitting in a wooden chair. His arms had been fastened to the arms of the chair tightly with rope, while another rope around his midsection kept him pinned to the back of the chair. Papyrus was standing at the counter with his back to Sans, humming serenely as he worked. He turned when he heard Sans stir.

 

“Oh good, you’re awake!” He said, his usual cheerfulness back stronger than ever.

 

Sans looked down at himself in utter confusion. “Papyrus, what - what is this -“

 

“Now don’t be alarmed,” Papyrus said casually, “I had to make sure you didn’t run off.”

 

Suddenly looking concerned, he bounded over to Sans, reaching out to tenderly touch his brother’s skull. “I didn’t hit you too hard, did I -”

 

Sans flinched away from Papyrus’ touch. “You HIT me!?” He couldn’t believe it. “Papyrus, what the hell!? You - You could have -“

 

“Oh no, no, don’t worry!” Papyrus said quickly. “I knew what I was doing! I’ve always had excellent control of my magic! I used just enough force to knock you out!” He giggled. “Not like it takes much to get you to sleep, you lazybones!”

 

When you’re the brother of a guy like Papyrus, you have to expect to put up with a lot of crap. And 99% of the time, Sans was more than willing to do just that. This was the 1%.

 

“Papyrus,” Sans said in a dangerously low voice, “untie me _right now_.”

 

“I will!” He turned away, spooning spaghetti onto a plate. “I will. Just as soon as you’ve eaten my spaghetti.” He turned back and held the plate out to Sans, smiling hopefully.

 

Sans stared at him, uncomprehending. “I - I _told_ you, I already ate. I’m full.”

 

“Now I’m _sure_ that isn’t true.” Papyrus was still smiling, but there was an edge to his voice, like the scary Papyrus from earlier might show up at any moment. “I’m _sure_ you have a _little_ room left for the spaghetti your brother made with _love_.”

 

_More like LOVE_ , Sans thought, but wisely left that crack unspoken. Instead he let out a disbelieving laugh as Papyrus pulled up another chair in front of him and sat down.

 

“Is - is this a joke? You getting back at me for all the times I’ve pranked you? Well you got me, okay? Consider me fully japed, now let me g - UMPH!” He was cut off as Papyrus took a forkful of spaghetti and suddenly jammed it into San’s mouth. Sans was so startled he swallowed without chewing.

 

Papyrus grinned as he readied another forkfull. “There we go! Good, right?”

 

Oh God, he was really serious about this. “Papyrus, wait a minute, you can’t -” His protests were muted as more spaghetti was shoved into his mouth.

 

“Shh, now don’t make a fuss.” Papyrus put the fork down to grab a napkin and dab away some of the sauce on San’s face. “This is going to happen either way, so you might as well try to enjoy it, right?”

 

Panic was rising in Sans’ chest. He felt trapped and humiliated, being fed like a baby against his will. When Papyrus raised the fork again, Sans made no further protests, this time opting to keep his mouth closed no matter what. He turned his head away from the fork. Nope. Nope. Bone zone is closed.

 

Papyrus sighed in frustration. “Now Sans, don’t be childish!” Sans almost opened his mouth to point out that’s big talk coming from a guy with a race car bed, but he caught himself in time.

 

Still holding the fork, Papyrus put the plate on the counter and used his free hand to lift Sans’ shirt a little, exposing his translucent magic gut. Sans twitched in alarm. What was he - ?

 

“You know Sans, you _really_ don’t want me as your enemy” Papyrus said casually, “I know _all_ your weaknesses.” He suddenly grinned wickedly as he took his free hand and began to lightly scratch the underside of Sans’ belly. Sans immediately tensed up. Oh no.

 

“Cootchie cootchie coo!” Papyrus said playfully. He spidered his long fingers up Sans’ belly, pushing the shirt back more. Sans trembled, squirming in the chair. No no no no no no

 

Papyrus suddenly jabbed his fingers into the soft belly. Sans threw his head back, shrieking with laughter.

 

“nnnnOOO HAHAHA STOP STOP STO -“ Papyrus took this opportunity to ram the fork into Sans’ open mouth, cackling triumphantly.

 

“Gosh, Sans,” Papyrus said with a laugh, “It’s so rare to see you like this. You’re always so cool and laid-back. I wonder…”

 

He put the fork aside with the plate and used both hands on Sans’ belly, tickling in earnest.

 

Sans gasped and screamed, struggling wildly, but the ropes held him firm. In desperation he tried to kick Papyrus, but Papyrus simply scooted up in-between his legs, closing the distance between them. He ruthlessly dug his fingers into Sans’ sensitive tummy, pressing and squeezing.

 

“Wowie, it’s been forever since we’ve had a tickle fight!” Papyrus said gleefully as Sans squirmed in his hands.

 

Sans remembered that back when they were just baby bones, sometimes arguments would turn into wrestling, which would turn into “tickle fights.” But the difference there was that Sans could actually fight back. This was not a fight. This was assault. This was weird and uncomfortable and it made Sans feel helpless and vulnerable and he hated it, he hated it and he wanted it to stop -

 

He felt tears streaming from his eyes and his face burned with shame. “P-Please,” he begged, “stop stop please pleaaaase I can’t stand it STOP!”

 

Papyrus did stop, this time. Sans collapsed in the chair, breathing heavily. He couldn’t hold back the sniffles and sobs. Papyrus sat back for a moment, watching Sans fondly. It made Sans’ stomach turn. Eventually Papyrus leaned forward, looking into Sans’ eyes.

 

“Now Sans, I’m going to give you a choice. You can eat, or we can go back to tickling.”

 

Sans took in a shaky breath. There was actually a third option, Sans knew. One Papyrus didn’t know about. Sans knew he could get out of this situation right now if he unleashed his full power. Hell, summoning even one Blaster might be enough to get Papyrus to back down.

 

But what if it wasn’t. What if Papyrus fought back. What if things escalated until -

 

No. No. He couldn’t do it. He couldn’t risk hurting his brother. Even if his brother saw fit to hurt him.

 

Desperately, he tried once again to reason with Papyrus.

 

“Why…why are you doing this? Come on, man. I-I’m your brother.”

 

Papyrus smiled gently. “Yes, you are. And you’re also my best friend. You’re very important to me, you know?”

 

He reached out and tenderly stroked Sans’ face, wiping away tears.

 

“I guess I just want you all to myself. It makes me so mad when I think of sharing you with others. _I_ want to be the one who makes you laugh, _I_ want to be the one who gives you good food, _I_ want to be the one that makes you happy and keeps you safe. That’s how I think it _should_ be. Just you and me. No one else.”

 

Sans stared at Papyrus, at a loss of words. “That’s…but P-Papyrus, you can’t treat me like this. You know that, right? It’s wrong.”

 

“Well! If you would just _listen_ to me, I wouldn’t have a reason to!” He picked up the fork and plate again. “Now, what’s it going to be?”

 

Sans let out a frustrated sigh. He knew he’d have better luck arguing with a brick wall. “Okay, okay, I’ll eat.”

 

“That’s better!” Papyrus smiled, scooting close and preparing another forkful of spaghetti.

 

Sans obediently ate everything on the plate, and didn’t even object when Papyrus came back with a second helping. At the third plate Sans began to protest again in earnest, but a simple poke at his sensitive stomach was enough to cow him. With the fourth plate, Sans was becoming desperate.

 

“Papyrus, come on,” Sans begged, “please, I can’t take anymore, my stomach…” It had grown considerably, the swollen blue bulge peeking out from under his shirt. “I _really_ don’t wanna know what happens if this thing bursts.”

 

“Come on, a few more bites? For me?” Papyrus urged the fork towards him. “I know you can do it!”

 

Sans closed his eyes in pain as he felt the magic stomach straining against him. But he obediently ate what Papyrus gave him.

 

“Good boy,” Papyrus crooned. Sans’ face burned with shame and he felt sick. He suddenly felt Papyrus’ hands on his belly and he tensed, expecting more tickling. But Papyrus just pressed his palms on Sans’ belly, gently rubbing the swollen stomach.

 

“Wh-What are you -”

 

“Shh, it’s okay,” Papyrus said, “It feels good, right? Doesn’t that feel good?”

 

It DID feel good but it was still weird and uncomfortable and it wasn’t normal brother behavior. Nothing about tonight had been normal brother behavior.

 

Papyrus chuckled and leaned forward, resting his elbows on the curve of Sans’ belly and looking at him lovingly.

 

“Well, I think we learned an important lesson today, didn’t we? Let _me_ feed you instead of Grilby’s, and you won’t have this problem again!”

 

Sans doubted that, but he’d smile and nod for the moment. “So…are we done?” He asked hopefully.

 

“Yes, I think we’re done. For now.”

 

“Will…will you untie me?” He smiled nervously. “Please?”

 

“Well you know, I was thinking about that and -“

 

Oh god oh god oh god Sans willed himself to stay calm, his heart hammering in his chest.

 

“ - I know you don’t like working as a sentry. Or working at all. So I thought, I’ll just tell everyone that you quit so you could laze around the house more. That way, I could keep you like this all the time! I mean, not like THIS exactly, I’d find a place more comfortable for you, but -”

 

Papyrus gave Sans a grin that was almost innocent.

 

“You’re just so cute like this, you know? And I’m sure no one would question it if you didn’t come out of the house for a long time.”

 

Sans trembled, knowing that Papyrus was 100% right. And he knew better now than to question if Papyrus would really go through with it.

 

“P-Papyrus but -“ he said desperately, “but I really LIKE working! I do! I-I like my job,and - and - I like working with YOU!”

 

It seemed Sans managed to hit upon the magic words with that last bit, because Papyrus clasped his hands in delight. “Oh brother, you mean it? Well in that case, I won’t deny you an honest day’s work!” He stood and began to undo the ropes holding Sans to the chair. Sans did his best not to weep with relief.

 

Once Sans was free, Papyrus glanced at the clock. “Goodness, it’s this late already?” He began to head towards the stairs. “I’ll be waiting for my bedtime story, Sans!”

 

“R-Right,” Sans said, rubbing his aching wrists, “I’ll uh, I’ll be right there.”

 

He slowly, shakily pushed himself out of the chair. He thought back to when he read Papyrus his bedtime story the night before. Everything had been - well, not _perfect_ , but at least where Papyrus was concerned, it felt _right_. It felt safe. What had happened in that little space of time between then and now? How did things get so screwed up? Had it always been like this, and he just didn’t notice?

 

“Sans.”

 

Sans jumped, his heart leaping into his throat. He turned around and saw Papyrus was about halfway up the stairs, watching him.

 

“Uh, y-yeah, bro?”

 

“If you were to leave - and I _know_ you would never hurt me like that - but if you _did_ ,” Papyrus spoke in an even voice, his smile never leaving his face, “I would find you. The Underground isn’t a very big place, after all. And then I’d have to punish you. And neither of us wants that, right?”

 

Sans swallowed and nodded mutely. Papyrus’ smile grew bigger.

 

“Good! See you in a few!” He bounded up the stairs cheerfully.

 

Sans stumbled over to the couch and sat down, head in his hands. It wouldn’t be a very good bedtime story if he started sobbing, so he figured he’d better get that out of the way now.

 

 

 

 

 

 

 

**Author's Note:**

> I think tonight Papyrus is going to get a story about how Fluffy Bunny needs to respect the boundaries of his brother, Sleepy Bunny!
> 
> EDIT: Be sure to check out [Caveatelli](http://archiveofourown.org/works/6828547) by Sora_Tatuya, a sequel to this fic, and then [Spirialini(ng out of control)](http://archiveofourown.org/works/6999079) by Lovova, a sequel to that sequel!

**Works inspired by this one:**

  * [Caveatelli](https://archiveofourown.org/works/6828547) by [Sora_Tayuya](https://archiveofourown.org/users/Sora_Tayuya/pseuds/Sora_Tayuya)




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